Rockets from Gaza fired on Tel Aviv and Jerusalem

Jerusalem and Tel Aviv were both attacked Friday but the rockets fired from Gaza fell short of their targets. Meanwhile, the Israeli army is arriving on the border with Gaza, ready for the order to invade. NBC's Martin Fletcher reports.

By NBC News staff and wire reports

Updated at 2:15 p.m. ET: On the third day of escalating violence between Israel and Gaza, air raid sirens cried out in Israel’s two largest cities, Jerusalem and Tel Aviv, as residents moved into underground shelters, NBC reporters on the scene said.

At least one rocket fired from Gaza toward Jerusalem landed outside the city, which is more than 60 miles from the Gaza Strip, according to NBC's Martin Fletcher. There were no injuries or damage. This was the first Palestinian rocket to reach the vicinity of Jerusalem since 1970.

"The rocket landed off the shores of Tel Aviv," a police spokesman told Reuters. This was the second attack on Tel Aviv in as many days, with rockets nearly hitting the city on Thursday.

The attacks, which Israel considers to be a major escalation, could lead to an Israeli ground invasion of Gaza.

Israel's military is considering waging a ground campaign. It started drafting 16,000 reserve troops on Friday, as Israel's cabinet authorized the mobilization of up to 75,000 reservists. Troops are massing on the border, and witnesses said they could see Israeli ships off Gaza's coast, NBC News' Ayman Mohyeldin reported.

The rocket attacks came just hours after Egypt’s prime minister visited the Gaza Strip to show support for Palestinians amid a cross-border conflict with Hamas militants that risks spiraling into an all-out war.

"Egypt will spare no effort ... to stop the aggression and to achieve a truce," Prime Minister Hesham Kandil said.

"Palestine is the heart of the Arab and Muslim world and the body is not healthy while the heart is sick," he added.

The Palestinian enclave of Gaza was attacked Friday, where the Interior Ministry took direct hits and civilians died. NBC's Richard Engel reports.

Kandil held the bloodied body of a child at a hospital before leaving the Gaza Strip.

But even as Kandil made his three-hour visit to the coastal enclave, a temporary cease-fire declared by Israel at Egypt’s request collapsed, with both sides accusing the other of violating it.

At least 19 Palestinians, including seven militants and 12 civilians, among them six children and a pregnant woman, have been killed in Israeli airstrikes. A Hamas rocket killed three Israelis in the town of Kiryat Malachi on Thursday.

Israeli Prime Minister Benjamin Netanyahu has said he is prepared to “take whatever action is necessary,” but Israel has also expressed a strong desire to preserve its peace with the new Egyptian leadership.

Overnight, the military said it targeted about 150 of the sites Gaza gunmen use to fire rockets at Israel, as well as ammunition warehouses, bringing to 450 the number of sites struck since the operation began Wednesday.

Hamas chief killedThe latest upsurge of violence in the long-running conflict began Wednesday when Israel killed Hamas' military mastermind, Ahmed Jabari, in a precision airstrike on his car. Israel then began shelling Gaza from land, air and sea.

Israel says its offensive was in response to increasing missile salvos from Gaza. Its bombing has not yet reached the saturation level seen before it last invaded Gaza in 2008, but Israeli officials have said a ground assault remains possible.

“We are going to continue hitting Hamas hard and we will continue to strike hard at the missiles targeted at Central and South Israel," Netanyahu wrote Friday on Twitter.

An Israeli ground offensive could be costly to both sides. In the last Gaza war, Israel devastated parts of the territory, setting back Hamas' fighting capabilities. But Israel also payed the price of increasing diplomatic isolation because of a civilian death toll numbering in the hundreds.

This week’s fighting has widened the instability gripping the region, further straining Israel-Egypt relations.